Network Communications News (NCN) May 2016 | Page 19

choosing the right rack

F E AT U R E

IP20 protection is sufficient in
a closed data centre. Here, it isn’t
necessary for the individual racks to be
lockable, as only authorised persons
have access. Access to individual racks
is controlled through an electronic
lock, a card reader, or a transponder.
Personalised access control via
a transponder card or a uniquely
assigned numeric code identifies who
had access to the server rack, and
when. Taking this a step further, a
dual control, counter-checking system
(‘four-eye-principle’) is also feasible,
where two people have to provide
identification at the same time.

How is heat dissipation
performed?
The technology inside the rack
produces waste heat, which has to
be dissipated to protect the sensitive
electronic components and increase
their service life.
If a single rack is to be cooled, a
climate control unit must be installed.
This blows the cooled air directly at and
in front of the server level. The rack must
have a closed (glass) door, so that the air
cannot escape into the room.
Meanwhile, perforated doors with a
cooling system are required for bayed
racks and rooms in order to extract the
cool air from the room and/or cold aisle.

How does the
power supply and
distribution work?
If a single rack is to be cooled, a
climate control unit must be installed.

Where is the rack located,
and how should it be
protected?
IT racks are installed not only in data
centres but also in offices, production
buildings etc.
The location of the rack defines the
protection requirements and safety class,
which is expressed in the international IP
(‘International Protection’) standard. If the
IT rack is in an office environment, access
protection as per IP20 (with a lockable
door) is sufficient. A rack in a production
building, however, needs to be lockable.
With IP55 protection, it also needs to be
safeguarded against dust and jets of water.

An uninterruptible power supply (UPS)
unit will filter out the voltage fluctuations
that are harmful to IT components. In
addition, the power supply can take over
temporarily during a power failure thanks
to its battery mode.

Power distribution units
(PDUs) then distribute the
power within the rack.
How are access to facility management
and integration into building
management systems achieved?
Facilities management typically
has to manage the monitoring of
external parameters. This includes
the temperature of the cooling water
supplied from outside to the air/
water heat exchangers for cooling
the IT racks.
If the climate control unit
for cooling the racks is an active
version, monitoring of the humidity
will be necessary.

Surveillance at the IT rack, eg. the
monitoring of temperature, smoke,
power consumption and vandalism,
must also be integrated into the building
management system. It is vital that the
monitoring solution supports standard
protocols such as SNMP (simple
network management protocol) for
the connection to DCIM (data centre
infrastructure management) software, or
OPC UA (object linking and embedding
for process control unified architecture
for linking to building control).

The use of the rack
determines its size
and dimensions.

Clive Partridge
began his career in
the merchant navy
before becoming a
project manager for
Siemens in Germany.
He joined Rittal in
1994 as a product
manager for electronic
and datacomms
enclosure products. His
experience of water
cooled rack products
and environmental
monitoring led to him
taking on the role of
technical manager for
Rittal’s IT business,
providing expert advice and sales support for colleagues
and customers alike.

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